Pipe joints for connecting metal fuel pipes or tubes used for fuel supply systems of automobiles or the like are conventionally known. As this kind of pipe joint, for example, one disclosed in Japanese Laid-Open Patent Publication No. 2005-172161 has been known.
The above pipe joint has an inlet along an axis of a pipe joint body in order to receive a pipe. The pipe inserted into the inlet is engaged with a retainer, a bulge portion of which protrudes through the pipe joint body, and thus is held in the pipe joint.
Patent Document 1: Japanese Laid-Open Patent Publication No. 2005-172161
Because the retainer is attached to the pipe joint body from a radial direction, retainer attaching holes are opened in a side surface. These openings are generally located within a substantially half circumferential length, and the remaining half is configured as a closed wall surface.
The pipe joint body is integrally molded from a synthetic resin. A part corresponding to the inlet hole in a mold for molding the pipe joint body is configured to have a pin shape (molding pin). A cross section of the inlet is circular, so that it is thought that a cross section of the molding pin is preferably circular.
However, as mentioned above, the retainer attaching holes are formed in only half of the side surface of the pipe joint body. Therefore, the half is an open area and the remaining half is a closed area, so that heat shrinkage immediately after molding is considerably different between the open side and the closed side. Naturally, the closed area is largely affected by the heat shrinkage, and therefore, if the molding pin is formed to have an accurate circle, formation of a circular inlet hole may be inhibited by the heat shrinkage after molding. That is, the shape of the molding pin should be designed with influence of the heat shrinkage in mind. More specifically, the shape of the molding pin has been configured such that a part corresponding to the open area is a perfect circle and a part corresponding to the closed area is a substantially ellipse bulging outwardly. However, it is never easy to manufacture the molding pin into the aforementioned shape, so that it is desired to resolve it earlier.